Disposable baby diapers have been on the market for 40 years, but for the first 15 of those, the most popular version was the European two-piece, or Swedish diaper, which had a plastic pant arrangement with a separate removable and disposable absorbent pad or core.
In the mid-1960's, Procter & Gamble Company developed and effectively commercialized the one-piece disposable diaper having a rectangular absorbent pad with an integral plastic backing sheet folded into a "wing"-shape and marketed under the trademark "PAMPERS". Such a product is illustrated by the Duncan U.S. Pat. No. 3,180,335.
Ten years later, in the mid-1970's, the shaped elastic leg diaper became popular and has dictated the baby diaper development for the last 15 years. This product is illustrated by the Buell U.S. Pat. No. 3.860,003.
During the last few years, at least nine specific significant changes have been made to the disposable baby diaper:
1) Dry-touch covers with transport sub-layers (Meyer U.S. Pat. No. 4,798,603). PA1 2) Frontal tapes with fit guides (Hirotsu U.S. Pat. No. 4,662,875). PA1 3) Elastic waist bands (Kievit U.S. Pat. No. 4,515,595). PA1 4) Multistrand elastic legs (Suzuki U.S. Pat. No. 4,425,127). PA1 5) Superabsorbent cores (Weisman U.S. Pat. No. 4,610,678) PA1 6) Leakage control end dams (Woon U.S. Pat. No. 4,296,750). PA1 7) Stretchable tapes (Jacobs U.S. Pat. No. 3,800,796). PA1 8) Gender specific cores (Weisman U.S. Pat. No. 4,673,402). PA1 9) Fecal control cuffs (Enloe U.S. Pat. No. 4,704,116).
Of these improvements, the most recent and technically intriguing are the dry-touch cover and the fecal control cuffs.
The dry-touch cover creates a body-contacting surface which is hydrophobic and, therefore, presents no moisture against the body of the infant wearing the diaper. To accomplish this end-result, the covers have been made of plastic film or of carded, melt-blown, spun bonded or hydroentangled hydrophobic fibers, to permit rapid pass-through of the fluid to the diaper cores which have been made particularly and effectively absorbent, so that the fluid can be entrapped in the core. The core is designed so that it reduces as much as possible the wet-back of the fluid, under pressure, toward the body of the infant.
This dry-touch cover can also be made more effective by increasing the thickness of the coverstock material as shown in the Brock U.S. Pat. No. 4,766,029, or by the utilization of the Procter & Gamble perforated plastic film illustrated by the Thompson U.S. Pat. No. 3,929,135.
The thickness of the coverstock material can also be increased by utilizing high-loft fibers as shown in the Muhlratzer U.S. Pat. No. 4,761,323 or, as in the Kimberly-Clark Meyer U.S. Pat. No. 4,798603, by introducing one or more sub-layers of material between the coverstock and the core to draw the fluid away from the coverstock by capillary action.
The thicker the caliper of the web of the coverstock, the more expensive it becomes (because of material costs and production costs) and, quite frequently, it also becomes stiffer. All of this renders it less desirable than a lightweight, thin coverstock material.
As for the fecal control feature, changes to the early wing-fold "PAMPERS" included upstanding edges as shown in Schroeder U.S. Pat. No. 4,246,900 and Buell U.S. Pat. No. 4,636,207. The barrier "cuffs" were first commercialized in Japan as illustrated by the Suzuki U.S. Pat. No. 4,834,704 and Igaue U.S. Pat. No. 4,822,435. More recent diapers have featured the barriers shown in the Enloe U.S. Pat. No. 4,704,116 and the Lawson U.S. Pat. No. 4,695,278.
The effectiveness of such a construction is in its ability to contain feces (which generally do not penetrate into the absorbent core as does urine), by preventing the feces from spilling over the edge of the diaper, soiling the infant's garments or the surrounding environment.
Each of the features referred to above, particularly the dry-touch cover and the fecal containment cuffs have been developed independently of each other, and it is the object of the present invention to improve the performance by decreasing the wet-back of the diaper and, at the same time, by providing better fecal containment. This is done by providing a multi-ply coverstock of thin web material, one web of which also provides the fecal containment cuffs. The end result is that the cost of the coverstock is significantly reduced, the pass-through of the fluid from the body-side into the core is enhanced, the wet-back of the fluid from the core back to the body is reduced, the feces are kept on the diaper, and the overall performance of the diaper is enhanced.
As significant as is the design with regard to performance, it also is important in that it is a major step in the source reduction of waste and in the consumption of less raw material, and thus it reduces the adverse environmental impact of disposing of disposable diapers.